1. Field of the Invention
The present invention relates to a battery pack accommodating a battery in a plastic-made outer casing, and particularly pertains to a battery pack to be attached to and projecting from electronic equipment such as a laptop-type personal computer to improve an anti-shock strength of a protruded portion.
2. Description of the Related Art
When a battery pack attachable to a laptop-type personal computer is attached so that the battery pack projects from the personal computer, a discharging capacity can be enlarged. When the battery pack is dropped in a state of being attached to the personal computer, such battery pack is subjected to a very strong shock. Such strong shock will deform the outer casing, and the deformed outer casing will cause damage to the battery. Thus, it is important to improve an anti-shock strength of the battery pack which is used for such an application. The present applicant has developed a battery pack intended to improve the anti-shock strength. Such battery pack is disclosed in JP 2004-327206-A.
FIG. 1 shows the battery pack disclosed in JP 2004-327206-A. The battery pack includes a casing 91 and a hollow cover 92, the casing 91 being composed of a first casing 91A and a second casing 91B. The first casing 91A, the second casing 91B, and the hollow cover 92 are respectively made of a plastic material. The first casing 91A has a battery storage portion 94 for accommodating a battery 93. The first casing 91A has a battery cover wall 95 in a position opposite to an end face of the battery 93 accommodated in the battery storage portion 94. The second casing 91B is longer in overall length than the first casing 91A, and has a protrusion 97 that projects outwardly from the battery cover wall 95 of the first casing 91A. The second casing 91B has a projecting end face wall 98 at a tip face of the protrusion 97. The hollow cover 92 is fixed between the projecting end face wall 98 of the second casing 91B and the battery cover wall 95 of the first casing 91A. The hollow cover 92 is formed in a hollow state of sealing an opening of a gap defined between the projecting end face wall 98 and the battery cover wall 95.
The battery pack is structured so that the hollow cover is fixed to the protrusion projecting outwardly from the battery storage portion and a hollow portion is defined by the protrusion and the hollow cover so that the shock is absorbed by the hollow portion. Since such structure ensures that when subjected to a large shock, the portion that absorbs the shock is not crushed and a strong shock like when dropped can be effectively absorbed, thus improving the strength resistance. Further, since such a battery pack enables the shock to be absorbed by the hollow portion defined outside the battery storage portion, the battery and other portions can be effectively protected without any damage to the inside battery storage portion even if the protrusion or the hollow cover of the second casing is damaged by a strong shock.